Apply T306747 to wmf wikis
# **ALTERs to run:** https://gerrit.wikimedia.org/r/c/mediawiki/extensions/GlobalBlocking/+/785376/1/sql/mysql/patch-globalblocks-timestamps.sql
# **Where to run those changes:** centralauth database only
# **When to run those changes:** any time
# **If the schema change is backwards compatible:** Yes
# **If the schema change has been tested already on some of the test/beta wikis:** beta cluster is running with the new schema
# **if the data should be made available on the labs replicas and/or dumps:** no change of the existing rules
This makes `gb_timestamp` a fixed length column and removes default of empty string from `gb_expiry`
Progress
[x] dbstore1008
[x] db2220
[x] db2218 master
[x] db2208
[x] db2200
[x] db2198
[x] db2187
[x] db2182
[x] db2168
[x] db2159
[x] db2150
[x] db2122
[x] db2121
[x] db2098
[] db1236 master
[] db1227
[] db1202
[] db1194
[x] db1191
[] db1181
[x] db1174
[] db1171
[] db1170
[] db1158 sanitarium master
[] db1155
[] clouddb1021
[] clouddb1018
[] clouddb1014